1. First of all disable all shortcuts for the menu pad, If this isn’t done it won’t work. Then go to the home screen where your wallpaper is.
2. Just to explain <- means left menu pad click and -> means right
3. The code you type in -> ( right menu pad) *  <- (left menu pad) <- (left menu pad) * <- left menu pad) *

*=Star key on keypad

Once you have done this it should open a menu that has; Service settings, Service info ,Service tests and text labels

The one that you want is service tests.

Some of the examples of what some of them do dependant on phone:

• Continuous Led(camera flash illumination)
• Real Time clock(sets it back to what it should be)
• And loads of other cool stuff

Have fun with the new stuff you can do with your Sony Ericsson hope this helps